> Your instructor was right not to give you any points, for your answer was wrong, as he demonstrated using Gauss’ law. You should, in science, believe logic and arguments, carefully drawn, and not authorities. You also read the book correctly and understood it. I made a mistake, so the book is wrong. I probably was thinking of a grounded conducting sphere, or else of the fact that moving the charges around in different places inside does not affect things on the outside. I am not sure how I did it, but I goofed. And you goofed, too, for believing me.

I've heard of "non-apologies," which are sneaky ways of sounding like one is taking responsibility and apologizing without actually apologizing or taking responsibility.

But this is the opposite-- Fenyman takes zero responsibility for having led the student astray, and in fact chastises the reader for appealing to his own authority. At the same time, he gives evidence for why he should not be trusted as an authority-- he goofed and doesn't even know why!

It's like a variation of an old one-liner comedy insult, something like: "I got news for you, we could both do better!"

Anyhow, I like it.